1. Field of the Invention
The invention relates to an image forming apparatus such as an analog or digital copying machine, a laser beam printer or a facsimile apparatus, irrespective of a single color or multi-color. Above all, it relates to the cleaning brush of cleaning means for removing a toner, paper dust, etc. adhering to an image bearing member, and an image forming apparatus provided with the same.
2. Related Background Art
There is known a method of causing a cleaning brush to abut against the upstream side of the distal end portion abutting position of a cleaning blade with respect to the movement direction of an image bearing member to thereby carry an untransferred toner (see Japanese Patent Application Laid-open No. S58-144875).
Also, there is known a method of uniformly wearing an image bearing member, and removing foreign substances or the like on this image bearing member (see Japanese Utility Model Registration No. 2520078).
However, even if in the aforedescribed construction, the cleaning brush is urged against the image bearing member, if a frictional contact force is not sufficient, a discharge product, etc. produced from a charger or the like adhere onto the image bearing member. Therefore, when the image forming apparatus is used first in the morning, there occurs a faulty image such as “image deletion” in which an image deleted, or “toner filming in which a toner or a component in the toner adheres onto the image bearing member. Also, as endurance progresses, uneven wear or a streak occurs to the surface of the image bearing member, or the discharge product, etc. piled in groove such as an injury or the toner or a component or the like in the toner adheres to the surface of the image bearing member, thereby causing the occurrence of a faulty image.
Further, in recent years, an image bearing member (a universal hardness value (HU) of 150 N/mm2 or greater) having had its surface hardened and aiming at a long life is used in an image forming apparatus. Therefore, from the initial state of the image bearing member, the frictional force between the image bearing member and a cleaning blade is high and further, as endurance progresses, the frictional force between the image bearing member and the cleaning blade rises. Therefore, the turning-up or nicked edge of the blade, fluttering or the like occurs, and another faulty image occurs, such as the slipping of the toner through the nip of the cleaning blade.
So, as means for maintaining the long life of the image bearing member and yet, reducing the frictional force between the cleaning blade and the image bearing member, there is a method of forming a number of streaks in accordance with the circumferential direction of the image bearing member, and carrying out a surface roughening process on the surface of the image bearing member. Likewise in this case, adhering substances such as the discharge product or the like produced from a charger or the like, or the toner or a component or the like in the toner is piled in a groove formed by the surface roughening, and a streak-like faulty image corresponding to this groove occurs.
Further, when a surface-roughened image bearing member is used, the time until such a faulty image occurs become markedly shorter, as compared with an image bearing member having had its surface not roughened.